Terminal Vim

At the moment Terminal Vim only has basic support. This means is that colors won't be automatically calculated based on your colorscheme. Instead, some preset colors are used depending on whether background is set to dark or light.

When set background=dark is used, the following highlight colors will be defined:

hi IndentGuidesOdd ctermbg=blackhi IndentGuidesEven ctermbg=darkgrey

Alternatively, when set background=light is used, the following highlight colors will be defined:

hi IndentGuidesOdd ctermbg=whitehi IndentGuidesEven ctermbg=lightgrey

If for some reason it's incorrectly defining light highlight colors instead of dark ones or vice versa, the first thing you should check is that the background value is being set correctly for your colorscheme. Sometimes it's best to manually set the background value in your .vimrc, for example:

colorscheme desert256
setbackground=dark

Alternatively you can manually setup the highlight colors yourself, see :help indent_guides_auto_colors for an example.